1. Field of the Invention
The present invention relates to a vehicle zone monitoring apparatus that detects physical bodies such as other vehicles, pedestrians, and animals that are present in the vicinity of the vehicle.
2. Description of the Related Art
Japanese Unexamined Patent Application, First Publication, No. 2001-6069, is a known example of a zone monitoring apparatus that detects physical bodies present in the vicinity of a vehicle that move, such as pedestrians and animals. This zone monitoring apparatus calculates the distance between the objects in the vicinity of the vehicle and the vehicle from images obtained by two infrared cameras, and then calculates the motion vector of the objects from the position data of the objects found in a time sequence. In addition, the apparatus detects the objects having a high possibility of colliding with the vehicle from the relationship between the direction of progress of the vehicle and the movement vector of the object.
In addition, Japanese Unexamined Patent Application, First Publication, No. 2001-108758, discloses technology in which objects are detected by eliminating zones that exhibit temperatures clearly different from the physical body temperature of a pedestrian from an infrared image photographed by a photographing device provided on the vehicle. In this technology, for objects extracted from portions that eliminate the zone exhibiting a temperature clearly different from the physical body temperature of a pedestrian, the apparatus determines whether or not the object is a pedestrian by further identifying the aspect ratio of the object.
However, in the conventional zone monitoring apparatuses described above, although objects that emit infrared light can be detected, detecting objects besides pedestrians and animals is a problem. These objects include ones that naturally emit heat such as vending machines, the telephone poles and lamp poles that have been heated by exposure to the sun during the day, and have a low importance in terms of the vehicle travel.
In particular, there is the problem that physical bodies that have a temperature approximately the same as the physical body temperature of a pedestrian or have an oblong shape that is the same as that of a pedestrian cannot be distinguished at all from pedestrians.
Furthermore, when pedestrians and animals having indefinite shapes are extracted from the objects by identifying their shape, there is the problem that improving the precision of the detection is difficult.
In consideration of the above problems, it is an object of the present invention to provide a vehicle zone monitoring apparatus that eliminates artificial structures by shape identification using reference images from the infrared image photographed by a photographing device provided on the vehicle, and detects the remaining objects as physical bodies that move, such as pedestrians and animals.